Many satellites and other spacecraft, as well as some terrestrial stationary and vehicle applications, such as seagoing vessels, can include one or more energy storage flywheel systems to provide both a backup power source and to provide attitude control for the vehicle. In such systems, each flywheel system is controlled and regulated to balance the electrical demand in the vehicle electrical distribution system, and may also be controlled in response to programmed or remote attitude (or torque) commands received by a main controller in the vehicle.
Many energy storage flywheel systems include one or more components that are rotationally mounted within a housing assembly. These components, which may be referred to as the rotating group, include, for example, an energy storage flywheel, a motor/generator, and a shaft. In particular, the energy storage flywheel and motor/generator may be mounted on the shaft, which may in turn be rotationally mounted in the housing assembly via one or more bearing assemblies. In many instances, the shaft is rotationally mounted using one or more primary bearing assemblies, and one or more secondary, or back-up, bearing assemblies. For example, in many satellite and spacecraft applications, the flywheel system may include one or more magnetic bearing assemblies that function as the primary bearing assemblies, and one or more mechanical bearing assemblies that function as the secondary bearing assemblies.
The rotating group in an energy storage flywheel system may rotate at several thousand revolutions per minute (rpm) during operation. For example, in some applications, the rotating group may reach rotational speeds of up to 100,000 rpm. Though highly unlikely, it is possible that one or more components or subsystems that make up the energy storage flywheel system may deteriorate, or otherwise become inoperable, which could result in damage to other components and subsystems.
To reduce the likelihood of such component or subsystem deterioration when placed in its end-use environment, energy storage flywheel systems are typically rotationally tested and certified in a test facility. During this testing, it is also possible, though highly unlikely, that one or more components or subsystems that make up the energy storage flywheel system may deteriorate or become inoperable.
Hence, there is a need for a system and method that will stop energy storage flywheel system operation during system testing if component or subsystem deterioration is sensed. Namely, a system and method that will remove energy from the rotating group in the event one or more energy storage flywheel system components or subsystems is sensed to be deteriorating, and/or a system and method that is configured to reduce the likelihood of falsely removing the energy from the rotating group. The present invention addresses one or more of these needs.